1. Field of the Invention
The present invention relates to a paper conveyor for feeding paper. More particularly, the present invention relates to a paper conveyor which can be used for supplying paper to business machines such as a laser printer and a copying machine and which can also be applied to, for instance, an automatic sheet setting machine which is used when a single piece of paper to be treated that is conveyed sequentially is collected until a plurality of pieces of paper are accumulated and a predetermined number of pieces of paper among them are automatically bound to carry out bookbinding. The present invention also relates to improvement in automatic sheet setting machines as described in Japanese Patent Publication (Kokai) Nos. Sho 62-124282, Sho 62-87396 and Sho 62-164703.
2. Description of Related Arts
The conventional paper conveyors of the types described above have been designed so that an automatic sheet setting machine can be connected thereto in different directions appropriately selected in accordance with situations and the direction in which paper is conveyed can be changed from one direction to another. Therefore, the conventional conveyors for feeding paper are usually provided with various switching mechanism for switching the direction in which paper is conveyed in order to change it.
For instance, when direction in which paper is to be conveyed must be selected from two directions, the conventional switching mechanisms for switching the direction in which paper is conveyed includes a guide member which is positioned at a branching portion of the paper conveyor and whose direction can be changed, and the direction in which paper is conveyed can be switched as by rocking the guide member from one direction to another to thereby switch the direction in which paper is guided.
However, the conventional paper conveyor of the above-described type has a problem that clogging of paper tends to occur due to difference in frictional resistance between the guide member of the switching mechanism for switching the direction in which paper is conveyed and the paper to be conveyed. Therefore, attempts to switch the direction in which paper is conveyed with a small radius of curvature in order to miniaturize the paper conveyor leads to further increase in the frictional resistance, as the result of which the clogging of paper tends to occur. This is one reason why the reliability of paper conveyance is deteriorated greatly. In addition, such switching mechanism for switching the direction in which paper is conveyed by the change of the direction of the guide member is disadvantageous because it cannot be applied to sheets made of a very soft material.
In order to ensure a more reliable conveyance of paper, it has also been proposed to construct the paper conveyor so that paper can be conveyed by holding it between two conveyor belts and the positions of the conveyor belts can be varied so as to enable the switching of the direction in which paper is conveyed. However, problems occur that it requires a very complicated construction to render the position at which the two conveyor belts variable, resulting in that cost for production increases and the reliability of change of the direction in which paper is conveyed becomes poor.